Bitumen (in some countries is also known as asphalt) is used mainly as a binder in road construction with a small percentage being used in roofing/waterproofing and vibration/anti-corrosion materials. Bitumen, including naturally occurring and refined bitumen obtained from distillation of crude oil, is usually semi-solid at room temperature and liquid when heated up. Conventionally, bitumen is stored and transported in bulk via tanks, pipes, trucks and ships that are maintained at elevated temperature of around 120 to 160° C. (ie. heated form), or at normal ambient temperature in steel drums or in polyethylene, polypropylene or paper bags (ie. cold form).
Storing bitumen in heated tanks and vessels consumes energy, thus making it expensive, whilst storing bitumen cold in drums leads to wastage as bitumen is very viscous and leaves behind residues. For example, the residues in steel drums may amount to about 3%. The top of the steel drum is usually cut open to enable easier decanting, thus leaving a destroyed drum with internal bitumen residue to be disposed of. On the other hand, packing of bituminous products in polyethylene, polypropylene or paper bags often leads to leakages during handling and transporting. Furthermore very often the polyethylene/ polypropylene bags do not melt and integrate into the bitumen but have to be fished out. With greater environmental concern, there is therefore a need for another method of packing, storing and transporting bitumen and bituminous materials in the cold form.
Further, handling and transporting of bituminous products in, for example 200 liters, steel drums can be difficult and hazardous if specialized drum handling equipment is not available at the transporter or end-user site.
US patent publication no. 2007/0027235, by Albert Marchal describes a consumable bitumen packaging material. The packaging material is made of a mouldable composition composed of 60.1-99.9 weight % of polymer, with 0.1-39.9% of the proportion being bitumen, and 0.1-39.9 weight % of a metallic charge. A packing container is moulded and after cooling it is filled with bitumen in a separate operation. The density of the packaging material is adjusted so as to prevent the packaging material from floating to the surface of the molten bitumen. The packaging material also has the required toughness, impact resistance and temperature stability for storage and transport.
Despite development in consumable bitumen packaging, there is still a need for another way of packaging bituminous materials in the cold form yet is clean safe, eco-friendly, energy saving and cost effective.